This invention relates to a supercharged engine and more particularly to an improved, compact, supercharged internal combustion engine.
There is a continuing demand on the designers of internal combustion engines to increase the power output of those engines and at the same time maintain both the engine compact and easily serviceable. Supercharging offers one way in which this goal can be achieved, although the use of engine driven superchargers as opposed to turbo-chargers gives rise to problems in arranging the drive for the supercharger and mounting it in an appropriate location where it can efficiently serve the induction system without interfering with the serviceability of the engine.
It is, therefore, a principal object to this invention to provide an improved, compact, supercharged internal combustion engine.
The inventors hereof have found that the overall engine construction can be simplified and the other goals still met if the supercharger performs additional functions than merely compressing the air delivered to the combustion chambers for combustion purposes. For example, engines frequently use air injection system for injecting air into the exhaust in order to improve the oxidation of unburned hydrocarbons and other potentially harmful pollutants. Also, engines frequently employ balance shafts in order to permit the use of smaller crankshafts and higher engine speed. Normally air pumps are separately driven from the engine to provide the air injection and the balancer shaft is built into the engine.
In accordance with a principal object to this invention, it is a purpose thereof to incorporate other functions into the supercharger of an engine, which normally had required separate components for their utilization.
It is a further object to this invention to provide an improved and compact supercharger for an engine that is mounted in such a way to make the engine accessible and to simplify the supply of the compressed charge to the combustion chambers of the engine.
It is a further object to this invention to provide a supercharger drive arrangement that incorporates a balancer shaft for balancing the engine.
It is a still further object to this invention to provide a supercharger arrangement herein the supercharger also supplies air for injection into the exhaust system to reduce pollutants.
A first feature of this invention is adapted to be embodied in a supercharged, twin overhead camshaft, inline internal combustion engine. The engine has a cylinder head that journals a pair of camshafts that rotate about parallel, longitudinally extending axes on opposite sides of the cylinder head assembly for operating valves therein. A cam cover encloses the portion of the cylinder head in which the camshafts are journalled. A supercharger is mounted above the cylinder head assembly and in an area generally overlying but primarily between the rotational axes of the camshafts.
In accordance with another feature of the invention, a supercharger is driven by an engine crankshaft for delivering a compressed air charge to the combustion chambers of the engine for combustion of fuel therein. In addition, a portion of the compressed air delivered by the supercharger is delivered to the exhaust ports of the engine for reducing the discharge of undesirable pollutants to the atmosphere.
In accordance with a still further feature of the invention, an engine is provided with a supercharger that is driven by the engine output shaft. The supercharger drive includes an elongated shaft having a balance mass thereon for balancing at least in part the unbalanced forces generated by the engine operation.